Hay

For weight loss and to reduce high glucose and insulin peaks, a diet based on hay/forage with a low sugar (ESC) and starch content is recommended for horses with IR/EMS. The Laminitis Site, and Dr Eleanor Kellon and the ECIR group, suggest that the total sugar and starch in the diet should not exceed 10% (on a dry matter basis). Fructans (the difference between ESC and WSC) do not cause insulin to increase and are currently (2018) considered unlikely to contribute to endocrinopathic laminitis. See Diet.

(Note that although the ACVIM consensus statement on EMS from 2010 suggests: "It is therefore recommended that NSC be calculated by adding starch and WSC percentages together, and this value should ideally fall below 10% of dry matter when feeding horses or ponies with EMS", because fructans do not cause insulin to rise, and because ESC and starch are digested in the small intestine, but fructans are fermented in the hind gut, NSC and WSC are not appropriate terms to describe horse food/diets. Instead ESC and starch (which can be lumped together as hydrolyzable carbohydrates), and fructans, should be used when describing horse food/diets.)

It depends on the moisture content of the hay at baling. Horse hay should be baled when it has between 12 and 15% moisture - hay with 15% moisture or less should not heat up, "sweat", become mouldy or change significantly in quality from the time it is baled, and should be fine to be fed to horses (or analysed) as soon as it is baled, as long as it is introduced gradually (as you would any other new feed). Hay baled with more than 20% moisture may "sweat" and lose nutrients for the first month after baling, but will generally be unsuitable for horses. See Is old hay better for horses with laminitis by Kathryn Watts - www.safergrass.org,

Is old hay better for laminitics?No - if correctly made with a water content less than 20%, there is unlikely to be any significant loss of NSC during storage. Old hay is however likely to have lower levels of the fat soluble vitamins A, D and E, and horses on a hay only diet (no grass) will usually need to have vitamin E supplemented. See Is old hay better for horses with laminitis by Katy Watts - www.safergrass.org

Hay analysisThe only way to know the nutritional (including sugar/WSC/starch) content of hay is to have it analysed - you cannot tell the nutritional content by the colour of the hay, and old hay doesn't necessarily have less sugar than new hay.TLS recommends having ESC analysed, rather than "sugar" or WSC. Companies that do this are ForagePlus in the UK (who send samples to Equi-Analytical), and Equi-Analytical in the USA.

For a horse with insulin dysregulation, the important figures on a hay analysis are ESC (simple sugars) and starch. A good hay analysis will report ESC, WSC and starch. The ECIR group recommends that combined ESC and starch should be below 10%. WSC = ESC plus fructans - there is currently little evidence that naturally eaten fructans increase insulin levels or contribute to the risk of laminitis - see Do fructans cause laminitis?

Equi-Analytical have common feed profiles from the many samples that they analyse on their website. Below are average and standard range figures for grass hay samples from 2000 to 2014. Note that these samples will include C4 as well as C3 hay, and therefore may not be particularly representative of northern European/UK hay, which will be mostly C3. See Equi-Analytical Common Feed Profiles.

​Commercial analysis of fructans may not be accurate:J Sci Food Agric. 2012 Feb 1. doi: 10.1002/jsfa.5555. [Epub ahead of print] (PubMed)Comparison of a colorimetric and a high-performance liquid chromatography method for the determination of fructan in pasture grasses for horses.Longland AC, Dhanoa MS, Harris PA."RESULTS: Pasture grasses (Phleum pretense, Festuca rubra, Dactylis glomerata, Lolium perenne) managed for grazing (sampled from April to November) and a further set managed for conservation (sampled in July) were analysed for fructan content by HPLC and the colorimetric technique. HPLC values ranged from 83 to 299 g fructan kg(-1) DM (mean 154); corresponding colorimetric values were 5-238 g fructan kg(-1) DM (mean 82). Discrepancies in values between the two methods varied with time of sampling and plant species. Comparison of selected samples before and after incubation with the fructan hydrolases used in the colorimetric method revealed incomplete fructan hydrolysis from the pasture grasses, resulting in underestimates of their fructan content."

Can typical values for minerals in hay be used?Hays analysed from the same area tend to have broadly similar profiles, e.g. high iron, low zinc and copper (although this is typical of most hays!), but actual mineral contents can vary considerably between fields or between years from the same field, so you cannot use your neighbour's or last year's hay analysis to accurately mineral balance your hay.

M. J. S. Moore-Colyer (1996). Effects of soaking hay fodder for horses on dust and mineral content. Animal Science, 63 , pp 337-342 doi:10.1017/S1357729800014892 4 bales of mature multi-species meadow hay were analysed. Sodium and calcium levels were similar in all 4 bales, but significant differences were found in levels of nitrogen (protein), phosphorus, potassium and magnesium between the 4 bales.​

Hay soaking

Minerals that are present in hay in a readily available ionic form will be leached out by soaking.Sugars (glucose, fructose and sucrose) are more readily reduced by soaking than fructans (Longland et al. 2011).

Vet Rec. 2011 Jun 11;168(23):618 (PubMed)Effects of soaking on the water-soluble carbohydrate and crude protein content of hayLongland AC, Barfoot C, Harris PA"The aim of this study was to determine the amounts of water-soluble carbohydrate (WSC), WSC constituents and protein leached from a range of U.K. hays soaked according to common practice. Initial hay WSC content ranged from 123 to 230 g/kg dry matter (DM). Soaking the hays for up to 16 hours in water at a mean temperature of 8°C resulted in a mean loss of 27 per cent (range 6 to 54 per cent) of hay WSC. The mean percentage losses of WSC constituents were 24 per cent (range 14 to 31) for fructan, 41 per cent (range 21 to 70) for fructose, 45 per cent (range 28 to 100) for sucrose and 56 per cent (range 29 to 100) for glucose. The mean crude protein content of the initial hays was 58.7 g/kg DM (range 30 to 86 g/kg DM) and this value was not affected significantly by soaking. Despite a mean WSC loss of 27 per cent, the WSC contents of seven of the hays remained above the suggested upper limit for laminitic animals of 100 g/kg DM."

A.C. Longland, C. Barfoot and P.A. HarrisThe effect of water temperature on loss of water-soluble carbohydrates from hay soaked in water for up to 16 hours 5th European Workshop Equine Nutrition 2010See Spillers website - The science behind Spillers

Research by Longland et al 2013 recorded a 28% loss of total simple sugars or ESC (glucose, fructose and sucrose) after 1 hour's soaking in 8'C water, which increased to a 53% loss (an additional 25% loss compared to 1 hour) after 16 hour's soaking. Using warmer water (16'C) increased total sugar losses to 48% after 1 hour and 74% after 16 hours (an additional 26% loss compared to 1 hour). As the hay samples started at less than 10% sugar and a 1 hour soak brought all samples to less than 6% sugar, there seems little benefit in soaking for more than 1 hour, particularly in hot weather when soaking may cause bacterial overgrowth/fermentation.

Is there any danger feeding soaked hay?Wet and warm conditions can lead to fermentation and bacterial growth. Always feed hay soon after soaking it and dispose of any uneaten hay out of horses' reach. According to With Horse Hay, Wetter Can Be Better - Eleanor Kellon VMD - www.wheelyhay.com"when soaking in hot weather, you can get bacterial overgrowth very rapidly, so in those cases don't soak longer than two hours."

Haylage

Is haylage suitable to feed to a laminitic pony?The fermentation process in correctly made haylage will significantly reduce the WSC levels from those in the freshly cut grass. Marksway Horsehage gives figures representing typical samples of <3% sugar and 1-2% starch for all their haylage products (the ACVIM consensus statement on EMS recommends feeding <10% combined WSC (sugar) and starch (all figures DM)).

In her book The Truth About Feeding Your Horse (2007), nutritionist Clare MacLeod says "Haylage can be a safe feed for laminitis-prone horses and ponies, but a high dry matter, high-fibre, low-protein haylage with low residual sugars should be selected."

If you decide to try haylage, as with all new feeds, introduce it slowly over several days, and monitor your horse closely.

Can haylage be soaked before feeding?Soaking haylage is not generally recommended as there is a risk of starting a secondary fermentation which could result in the proliferation of undesirable micro-organisms. The sugar and starch content in correctly made haylage is usually low enough that further reduction should not be necessary for most laminitic horses.

All About Hay and Haylage - Nic Barker, Rockley Farm blog Nov 2011"Haylage need not be soaked because (a) high levels of water soluble sugars are not present and (b) once wet, it goes off and becomes unpalatable extremely quickly"

From Equine Applied and Clinical Nutrition - R Geor, P Harris, M Coenen 2013 p 378 - silage or haylage with a high moisture content can undergo a process of secondary fermentation within hours at high temperatures or within 2-5 days at low temperatures.

Heel

Heel first landingDebra Taylor and Pete & Ivy Ramey advocate returning a horse to turnout and in-hand exercise following laminitis when they "have been trimmed, stabilized and have a heel first landing in boots" (Hoof Rehabilitation Protocol - Debra Taylor, Pete & Ivy Ramey). So it's important to recognise a heel first landing:

Equine Veterinary Journal, 43: 536–542 2011The effect of hoof angle variations on dorsal lamellar load in the equine hoofRamsey G, Hunter P, Nash MReasons for performing study: In the treatment of laminitis it is believed that reducing tension in the deep digital flexor tendon by raising the palmar angle of the hoof can reduce the load on the dorsal lamellae, allowing them to heal or prevent further damage.Conclusions and potential relevance: The models in this study predict that raising the palmar angle increases the load on the dorsal laminar junction. Therefore, hoof care interventions that raise the palmar angle in order to reduce the dorsal lamellae load may not achieve this outcome.Vet Clin North Am Equine Pract. 2010 Aug;26(2):391-405. (PubMed)Clinical presentation, diagnosis, and prognosis of chronic laminitis in Europe.Eustace RA. Raising the heels will put the alignment of the phalangeal bones further out of alignment, risks increasing compression at the coronet and further shearing of the laminae at the toe, leading to further rotation.

Heparin

Am J Vet Res. 2010 Dec;71(12):1462-7 (PubMed)Effect of heparin administration on urine protein excretion during the developmental stage of experimentally induced laminitis in horsesUberti B, Pressler BM, Alkabes SB, Chang CY, Moore GE, Lescun TB, Sojka JE"OBJECTIVE: To investigate the effects of heparin administration on urine protein excretion during the developmental stages of experimentally induced laminitis in horses.ANIMALS: 13 horses. Procedures-Horses received unfractionated heparin (80 U/kg, SC, q 8 h; n=7) or no treatment (control group; 6) beginning 3 days prior to induction of laminitis. All horses were given 3 oligofructose loading doses (1 g/kg each) at 24-hour intervals and a laminitis induction dose (10 g of oligofructose/kg) 24 hours following the final loading dose (designated as 0 hours) via nasogastric tube. Serum glucose and insulin concentrations were measured before administration of the first loading dose (baseline) and at 0 and 24 hours; urine protein-to-creatinine (UP:C) ratio was determined at 0 hours and every 4 hours thereafter. Lameness was evaluated every 6 hours, and horses were euthanized when Obel grade 2 lameness was observed.RESULTS: Mean±SD time until euthanasia did not differ significantly between the heparin-treated (28.9±6.5 hours) and control (29.0±6.9 hours) horses. The UP:C ratio was significantly increased from baseline at 20 to 28 hours after induction of laminitis (ie, 4±4 hours before lameness was evident) in control horses but did not change significantly from baseline in heparin-treated horses. Serum glucose or insulin concentration did not change significantly from baseline in either group.CONCLUSIONS AND CLINICAL RELEVANCE: Urine protein excretion increased during the developmental stages of carbohydrate-induced laminitis in horses; administration of heparin prevented that increase, but did not delay onset or decrease severity of lameness."Journal of Veterinary Emergency and Critical Care 19(1) 2009, pp 113–119 (Full)Evaluation of low-molecular-weight heparin for the prevention of equine laminitis after colic surgeryde la Rebiere de Pouyade G, Grulke S, Detilleux J, Salciccia A,Verwilghen DR, Caudron I, Gangl M, Serteyn DDA

Boots that come in small sizes:Equine Fusion boots start from 66-75 mm in length, and can be used for riding and turnout - see The Saddlery ShopEasyboot Transition boots start from 89 mm wide x 93 mm long and can be used for turnout/rehabilitation and light hacking - see EasyCare Inc

Horses sometimes come to TLS for help that are suspected of having laminitis, but they turn out to have a broken back or forward hoof pastern axis, and/or navicular syndrome, which is responsible for their lameness.

Hoof wall surface temperature

Is hoof wall surface temperature (HWST) a useful indication of laminitis?Increased hoof wall surface temperature is often seen in acute (and flared up chronic) laminitis cases. However, horses without laminitis can have fluctuations in HWST throughout the day, with differences being measured between feet. The measurement of HWST has been validated as a non-invasive index of blood flow in the foot by researchers, but under ambient temperature-controlled conditions.

Rosenmeier JG, Strathe AB, Andersen PHEvaluation of coronary band temperatures in healthy horsesAm J Vet Res. 2012 May;73(5):719-23. doi: 10.2460/ajvr.73.5.7194,320 coronary band temperatures (CBT) were obtained from 6 horses fed different diets. The CBT ranged from 9.6° to 35.5°C. Coronary band temperature followed a diurnal pattern and was positively associated with ambient temperature but was not associated with diet. CBT of healthy horses varied significantly during the day and among limbs."

Insulin-Induced Laminitis - An investigation of the disease mechanism in horses by Melody de Laat, Martin Sillence, Catherine McGowan and Christopher Pollitt - RIRDC December 2011 (choose "Download PDF") (see also Equine laminitis: Induced by 48 h hyperinsulinaemia in Standardbred horses de Laat et al. 2010)Hoof wall surface temperature was monitored in (insulin-sensitive) horses with hyperinsulinaemia-induced laminitis (insulin > 700 µIU/ml) - the ambient temperature was kept constant at all times (15.9 +/- 0.4'C). The HWST varied from around 26'C to 17'C over 48 hours in the control horses, with a gradual decrease in temperature. The HWST in the hyperinsulinaemic horses increased over the first 12 hours from around 22'C to around 27'C then remained elevated (see p13). The elevated HWST results indicate that there is a vascular component to the development of insulin-induced laminitis.

The reason for hyperhidrosis in PPID is not fully understood, but suggestions include:physical pressure of the enlarged pars intermedia on the thermoregulatory centre of the hypothalamus,thermoregulatory response to the long hair coat (but PPID horses that are clipped or in a cool environemnt continue to sweat),effect of increased beta-endorphin.

Hypertrichosis/hirsutism and hair coat changes

Hirsutism (hypertrichosis) - an abnormally long, thick, often curly coat that fails to shed - is considered the most unique and specific clinical sign of PPID, and therefore diagnostic of the illness, but is now considered an advanced sign of PPID and may be one of the last signs to be seen.

More subtle changes to the hair coat often develop before hirsutism:

patchy longer hairs, particularly on the head, neck and lower legs,

hanging on to the winter coat for longer than other horses (delayed shedding) (and developing a winter coat before other horses?).

incomplete or patchy shedding.

A lightening in coat colour may be seen in horses with darker coats.

The reason for hair coat changes is not known, but suggestions include:pressure on the hypothalamic thermoregulatory centre by the enlarged pituitary gland (Menzies Gow 2006);increased α-MSH secretion (Lloyd Inc 2008) from the pars intermedia through loss of dopaminergic inhibition;excessive plasma cortisol (Menzies Gow 2006) (but plasma cortisol is often normal when tested);excessive melatonin (Menzies Gow 2006);increased production of androgens by the adrenal glands (Lloyd Inc 2008).

J Vet Diagn Invest. 2007 Jan;19(1):128-32. (PubMed)Hypertrichosis in a horse with alimentary T-cell lymphoma and pituitary involvement.Mitsui I, Jackson LP, Couëtil LL, Lin TL, Ramos-Vara JA."At necropsy, the mare had hypertrichosis and the pituitary gland was diffusely enlarged. Histologically, neoplastic lymphocytes infiltrated the gastrointestinal mucosa, mesenteric lymph nodes, and the pituitary gland. In addition, there was hyperplasia of the pituitary gland pars intermedia. Pituitary adenoma was not present. Hypertrichosis in this case could have been triggered by a combination of adenomatous hyperplasia of pars intermedia and lymphoma resulting in disruption of the hypothalamic dopaminergic tone or disruption of the hypothalamic thermoregulatory center."NB PPID does not usually involve lymphoma - this is thought to be the first report of lymphoma affecting the pituitary gland of a horse.

Is an abnormal haircoat always diagnostic of PPID?No - according to Dianne McFarlane a long haircoat is not an absolute diagnosis of PPID - it is highly suggestive in an old horse but other things can cause the haircoat to not shed appropriately. She has found that horses that are very debilitated/malnourished may test positive for PPID and show clinical signs of PPID including not shedding normally, but once they are back to a good weight and more healthy they no longer test positive for PPID, shed their coat normally, and when their pituitary glands have been examined at post mortem they have been normal. She suggests that the stress of being debilitated may affect their endocrine axis and affect their haircoat.See Is it PPID or is it EMS?

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